The Mail Box Store of New Castle is always looking for ways to help our customers save money. The Mail Box Store of New Castle coupons are a great way to make your visit more valuable and we’re constantly changing and updating our coupons, so check back regularly to find other fantastic savings on Document Shredding, Notary Public, Promotional Products, U-Haul Rental, Mailbox Rental, Antique Shipping and more!.